Judo was part of the curriculum at Downside School in Purley, South London. It wasn't considered a sport, it was considered a life skill.
I was around 8 when Kingsley Hopkins became my judo teacher. He was taught by the man who brought judo to the UK, who had been taught by the man who invented it. It wasn't seen simply as a means of self-defence, but as a facility to improve somebody's way of life - maximising efficiency, minimising effort.
Kingsley was an old-fashioned teacher. We had a canvas-covered mat with a wooden edge and he would get us to do breakfalls on a wooden floor. They wouldn't do that today.
His view was that anything we learned on the mat we could adapt in life. He taught us ways of moving that would enable us to open a heavy door, for example; simple things that we could incorporate into everyday life.
He introduced me to the outdoors. When I said I didn't have any equipment, he told me I didn't need it. During the Second World War, he had fought in Burma with no equipment and just made do.
We cooked edible plants together, and he introduced me to the concept of how to take care of myself and not get sick. During the war, he spent time in the desert and had two mess tins. One he used as a lid, so flies never fell on the food and he never got ill. It is these kinds of things, small but significant, which have stayed with me.
He was my mentor. My family was wonderful but I had conversations with Kingsley that you couldn't have with a parent. The most important thing he taught me was that when you're researching something, learn all you can: go to libraries, read everything, find experts.
I wasn't academic. School didn't tackle the subjects I was interested in. I worked hard in the things that inspired me but Latin didn't inspire me. That's a lesson I've taken with me in life: if you can inspire someone, they'll teach themselves.
There have been times when judo has kept me safe on my travels. I remember falling off a cliff in the Peak District and what I knew about breaking a fall helped me. There have been times when I've been in a corner of the world and judo has made the difference, not only in terms of being able to extricate myself physically from a situation but also by giving me the confidence to stand up to something.
I left Downside at 13 and went to Reigate Grammar, where I started the judo club. I remember running along one day when I was there, and someone a few years older tripping me up and laughing as I flew through the air. But I landed, did a judo roll and carried on running. It's a hidden skill.
I didn't go on to university. There was nothing I wanted to study. Or so I thought. Nobody had told me about anthropology or ethnobotany, subjects I would have been interested in.
Kingsley and I stayed in touch until his death around 30 years ago. He was in his seventies then. He had a heart attack on the judo mat and passed away the next morning. I think of him every day.
Ray Mears was talking to Kate Bohdanowicz. His book My Outdoor Life (Hodder amp; Stoughton, pound;20) is out now. To learn more about judo, contact the British Judo Association.
Born 7 February 1964, Kenley, South London, England
Education Downside School, Purley, South London; Reigate Grammar School, Surrey
Career Survival expert, woodsman, instructor, author and television presenter